Bones, Muscles, and Skin
Table of Contents
Body Organization and Homeostasis
The Skeletal System
Diagnosing Bone and Joint Injuries
The Muscular System
The Skin
Bones, Muscles, and Skin
Section 1: Body Organization and
Homeostasis
• Think about how many parts of
your body are involved in getting and
eating your lunch
• Your body is always busy and each
part of the body has a specific job to
do
• All parts of your body work together
so smoothly that you don’t even
notice it
• The smooth function of the body is
due to the organization of your body
The levels of organization in the
human body consist of cells,
tissues, organs, and organ
systems
Bones, Muscles, and Skin
Cells
• The cell is the basic unit of structure and function in a
living thing
• The human body has about 1 trillion cells
• Cells cannot be seen without a microscope because they
are so small
Bones, Muscles, and Skin
Structures of Cells
• Cell Membrane: outside boundary of the cell
• Nucleus: control center that directs the cell’s activities
• Cytoplasm: Jelly-like clear liquid contained in the cell that
contains many structures called organelles
Bones, Muscles, and Skin
Functions of Cells
• Cells carry on processes that keep organisms alive
• Ex: Molecules from digested food undergo chemical
reactions that release energy for the body’s activities
• Cells grow and reproduce
• Cells get rid of waste products
Bones, Muscles, and Skin
Tissues
• A tissue is a group of similar cells
that perform the same function
• There are 4 basic types of tissues
• Muscle Tissue – contract or
shorten, carries out movement
• Nervous Tissue – carries
electrical messages back and
forth between the brain and other
parts of the body
• Connective Tissue – Provides
support to the body and connects
all its parts (ex: bone, fat, blood)
• Epithelial Tissue – covers
surfaces of your body inside and
out (ex: skin, lining of organs)
Bones, Muscles, and Skin
Organs and Organ Systems
Organ: Structure that is composed of different types of tissue
working together to do the same job (ex: heart, lungs, kidneys, skin)
Organ System: Group of organs that work together to perform a
major function (ex: heart is part of the circulatory system)
Bones, Muscles, and Skin - Body Organization and Homeostasis
Organs and Organ Systems
Each organ in your body is part of an organ system, which is
a group of organs that work together to perform a major
function.
Bones, Muscles, and Skin
Homeostasis
Homeostasis is the body’s tendency to keep an internal
balance. Homeostasis is the process by which an
organism’s internal environment is kept stable in spite of
changes in the external environment.
Example: Body temperature, blood sugar levels, water levels,
blood pressure, etc.
Bones, Muscles, and Skin
Maintaining Homeostasis
Your body has a variety of ways to maintain homeostasis:
 sweat
 shiver
Bones, Muscles, and Skin
Stress and Homeostasis
Sometimes things can happen to disrupt homeostasis. As a
result, your heart might beat more rapidly or your breathing
may increase. These reactions of your circulatory or
respiratory systems are signs of stress.
Stress is the reaction of your body to potentially threatening,
challenging or disturbing events.
Adrenaline is a chemical released by your endocrine system
in response to stress. Adrenaline gives you a burst of
energy and prepares your body to take action.
Your body reacts to Stress!!
Bones, Muscles, and Skin - Body Organization and Homeostasis
Outlining
An outline shows the
relationship between main
ideas and supporting ideas.
As you read, make an outline
about body organization and
homeostasis. Use the red
headings for the main ideas
and the blue headings for the
supporting ideas.
Body Organization and Homeostasis
I. Cells
A. Structures of Cells
B. Functions of Cells
II. Tissues
III. Organs and Organ Systems
IV. Homeostasis
A. Homeostasis in Action
B. Maintaining Homeostasis
C. Stress and Homeostasis
Bones, Muscles, and Skin - Body Organization and Homeostasis
Cell Specialization
Click the Video button to watch a movie
about cell specialization.
Bones, Muscles, and Skin
End of Section:
Body
Organization and
Homeostasis
Bones, Muscles, and Skin
Section 2: The Skeletal System
• Just like a building you have
a framework called a skeleton
• Your skeleton is made up of
all the bones in your body
(skeletal system)
• You have 206 bones in your
body
Bones, Muscles, and Skin - The Skeletal System
What the Skeletal System Does
Your skeleton has five major
functions. It provides shape and
support, enables you to move,
protects your organs, produces
blood cells, and stores minerals
and other materials until your body
needs them.
Bones, Muscles, and Skin
Shape and Support
• Your skeleton determines the
shape in your body
• The backbone (vertebral column)
is the center of your skeleton
• You have 26 small vertebrae that
connect with each other all the way
up your vertebral column
• Like a beaded necklace, the
vertebral column allows your body
to move and bend
• If your backbone was just one
bone, you would not be able to
bend
Bones, Muscles, and Skin
Movement and Protection
• Your skeleton allows you to move
• Most bones have muscles attach to allow you to move
• Bones also protect the vital organs in your body
• Ex: the skull protects the brain
Bones, Muscles, and Skin
Production and Storage of Substances
• Some of your bones produce substances that your body needs
• The long bones of your arms and legs are like factories that make
all different kinds of cells
• Bones also store minerals like calcium and phosphorous
• When the body needs these minerals, the bones release small
amounts
Bones, Muscles, and Skin
Immovable and Movable Joints
• A joint is a place in the body where two
bones come together
• Joints allow bones to move in different
ways
• There are two types of joints in the body
1.
Movable: allows wide range of
movement, held together by
ligaments
• Cartilage is found at the end of
bones and protects the bones from
rubbing together
2.
Immovable: Some joints between
bones allow little to no movement
like the bones of the skull
Bones, Muscles, and Skin - The Skeletal System
Joints of the Skeleton
A joint is a place in the body where two bones come
together. Joints allow bones to move in different ways.
Bones, Muscles, and Skin - The Skeletal System
Bones—Strong and Living
Bones are complex living structures that undergo growth and
development.
Bones, Muscles, and Skin
Bone Structure
• Sketch the a long bone such as the femur
Compact Bone: beneath the outer layer is a hard
dense layer of the bone called the compact bone.
Small canals run through the compact bone that
carry blood vessels and nerves
Spongy Bone: a layer of bone just inside the
compact bone that is lightweight but strong. Much
of spongy bone is found at the ends of long bones
and contains red bone marrow which produces red
blood cells
Medullary Cavity: carries yellow bone marrow
which stores fat
Bones, Muscles, and Skin
Bones Strength
• The structure of bone makes it strong and lightweight
• 20% of a person’s body weight is comprised of bone
• Bones get their strength partly from the minerals like
phosphorous and calcium
Bones, Muscles, and Skin
Bone Growth
• Bones are alive because they contain
cells and tissues like blood and nerves
• Bones also form new bone tissue as
you grow
• Sports contribute to the strength of
bones by stimulating new growth in your
bone tissue
• New bone tissue will form after you
have an accident such as breaking a
bone in your body
Bones, Muscles, and Skin
Bone Development
• When you were an infant, your skeleton was primarily
cartilage
• Over time, most of the cartilage was replaced with bone
Bones, Muscles, and Skin
Taking Care of Your Bones
• A combination of a balanced diet
and regular exercise are important
for a lifetime of healthy bones
1.Diet – A well-balanced diet
includes lots of calcium and
phosphorous to keep your bones
healthy (meats, whole grains, leafy
green veggies, and dairy)
2.Exercise – Plenty of exercise
provides your bones with the
opportunity to stimulate bone
growth (weight bearing exercise)
Bones, Muscles, and Skin
Osteoporosis
• As people grow older, they
lose some of the minerals stored
in their body
• This mineral loss can lead to
osteoporosis
• Osteoporosis is a condition in
which the body’s bones become
weak and break easily (hip, spin,
wrist)
• Osteoporosis is more
common in women than in men
• Regular exercise and a wellbalanced diet can help prevent
osteoporosis
Bones, Muscles, and Skin - The Skeletal System
Movable Joints Activity
Click the Active Art button to open a browser window and
access Active Art about movable joints.
Bones, Muscles, and Skin - The Skeletal System
Asking Questions
Before you read, preview the red headings. In a graphic
organizer like the one below, ask a what or how question for
each heading. As you read, write answers to your questions.
Question
Answer
What does the skeleton do?
The skeleton provides shape and support, helps
you to move, protects organs, produces blood
cells, and stores minerals and other materials.
Joints can move forward or backward,
in a circle, in a rotating motion, and in a
gliding motion.
How do joints move?
How strong are bones?
Bones can absorb more force without
breaking than granite or concrete.
What can I do to care for my bones?
Eat a well balanced diet and get
plenty of exercise.
Bones, Muscles, and Skin
End of Section:
The Skeletal
System
Bones, Muscles, and Skin - Diagnosing Bone and Joint Injuries
Comparing and Contrasting
When you compare and contrast things, you explain how
they are alike and different. As you read, compare and
contrast X-rays and MRIs by completing a table like the one
below.
Procedure
X-Rays
MRI
Effect on body cells
Can cause damage
Causes no damage
Types of injuries
identified
Bone (fracture and dislocation)
Bone and soft tissue
How they work
Pass through soft tissue and
are absorbed by bone; bone
shows on film
Cost
Low cost
Magnetic energy causes atoms
to vibrate, which forms a pattern
that is converted into an image
High cost
Bones, Muscles, and Skin - Diagnosing Bone and Joint Injuries
Links on Medical Technology
Click the SciLinks button for links on medical technology.
Bones, Muscles, and Skin
Section 3: Diagnosing Bone and Joint
Injuries
Bones, Muscles, and Skin
Common Skeletal System Injuries
Bones, Muscles, and Skin
Fractures, Dislocations and Sprains
Bones, Muscles, and Skin
Identifying Injuries
Bones, Muscles, and Skin
Treating Injuries
Bones, Muscles, and Skin
End of Section:
Diagnosing Bone
and Joint Injuries
Bones, Muscles, and Skin
Section 4: The Muscular System
Bones, Muscles, and Skin
Types of Muscle
Bones, Muscles, and Skin
Skeletal Muscle
Bones, Muscles, and Skin
Smooth Muscle
Bones, Muscles, and Skin
Cardiac Muscle
Bones, Muscles, and Skin - The Muscular System
Muscles at Work
Because muscle cells can only contract, not extend, skeletal
muscles must work in pairs. While one muscle contracts, the
other muscle in the pair relaxes to its original length.
Bones, Muscles, and Skin
Muscles Work in Pairs
Bones, Muscles, and Skin
Muscular Strength and Flexibility
Bones, Muscles, and Skin - The Muscular System
Previewing Visuals
When you preview, you look ahead at the material to be
read. Preview Figure 15. Then, in a graphic organizer like the
one below, write three questions that you have about the
diagram. As you read, answer your questions.
Types of Muscle
Q. How does skeletal muscle help my body move?
A. Skeletal muscles are attached to the ends of bones and provide the
force to move them.
Q. Where is smooth muscle found?
A. The inside of many internal organs
Q. Why is cardiac muscle considered a special type?
A. It is found only in the heart; it is like smooth muscle because it is
involuntary and like skeletal muscle because it is striated.
Bones, Muscles, and Skin - The Muscular System
Skeletal Muscles
Click the Video button to watch a movie
about skeletal muscles.
Bones, Muscles, and Skin - The Muscular System
More on Muscle Types
Click the PHSchool.com button for an activity
about muscle types.
Bones, Muscles, and Skin
End of Section:
The Muscular
System
Bones, Muscles, and Skin
Section 5: The Skin
Bones, Muscles, and Skin
Skin Functions
Bones, Muscles, and Skin - The Skin
The Epidermis
The skin is organized into two main layers: the epidermis and
the dermis.
Bones, Muscles, and Skin
The Epidermis Structure and Function
Bones, Muscles, and Skin
The Dermis
Bones, Muscles, and Skin
Caring For Your Skin
Bones, Muscles, and Skin - The Skin
Sunscreen Ratings
The graph shows how
sunscreens with different sun
protection factor (SPF) ratings
extend the time three people can
stay in the sun without beginning
to get a sunburn.
Bones, Muscles, and Skin - The Skin
Sunscreen Ratings
Reading Graphs:
What does the height of each
bar in the graph represent?
The height of each bar
represents the amount of time
that person can spend in the
sun before burning.
Bones, Muscles, and Skin - The Skin
Sunscreen Ratings
Interpreting Data:
How long can person B stay
in the sun without sunscreen
before starting to burn? With
a sunscreen of SPF 4? SPF
15?
20 minutes; 80 minutes; 5
hours
Bones, Muscles, and Skin - The Skin
Sunscreen Ratings
Inferring:
Suppose that person C was
planning to attend an all-day
picnic. Which sunscreen
should person C apply? Use
data to support your answer.
Person C would need to use
SPF 15 sunscreen because
SPF 4 would protect the
individual for only four hours.
Bones, Muscles, and Skin - The Skin
Sunscreen Ratings
Calculating:
Which is more effective at
preventing a sunburn–a
sunscreen with SPF 4 or one
with SPF 15? How much more
effective is it? Show your work.
SPF 15 is 3.75 times more
effective at preventing sunburn.
Calculations: 2.5 hours compared
to 40 minutes, or 150 minutes/40
minutes = 3.75; 5 hours compared
to 80 minutes, or 300 minutes/80
minutes = 3.75
Bones, Muscles, and Skin - The Skin
Sunscreen Ratings
Drawing Conclusions:
What does the number in the SPF
rating stand for? (Hint: Note the length
of time each person can stay in the sun
without sunscreen, and compare this value
to the length of time each can stay in the
sun using SPF 4. Then do the same for
SPF 15.)
It stands for the level of protection
against sunburn—the higher the
level, the greater the protection.
SPF 4 means a person can safely
stay four times as long in the sun;
SPF 15—15 times as long.
Bones, Muscles, and Skin - The Skin
Identifying Main Ideas
As you read the section titled “The Body’s Tough Covering,”
write the main idea—the biggest or most important idea—in a
graphic organizer like the one below. Then write five
supporting details. The supporting details give examples of
the main idea.
Main Idea
The skin has several important functions.
Detail
The skin forms a
barrier against
disease-causing
microorganisms
and loss of
fluids.
Detail
The skin helps
the body
maintain a
steady
temperature.
Detail
Detail
The skin helps
to eliminate
wastes through
perspiration.
The skin
contains nerves
that gather
information
about the
environment.
Detail
Skin cells
produce
vitamin D that
helps your
body absorb
calcium.
Bones, Muscles, and Skin - The Skin
Links on the Skin
Click the SciLinks button for links on the skin.
Bones, Muscles, and Skin
End of Section:
The Skin
Bones, Muscles, and Skin
Graphic Organizer
Muscles
can be
Smooth
muscles
Involuntary
muscles
Voluntary
muscles
include
include
Cardiac
muscles
Skeletal
muscles
Bones, Muscles, and Skin
End of Section:
Graphic Organizer